It is important, for saving time and costs, but also for safety, to be able to detect the presence of an optically invisible network and to locate it accurately, without digging the ground or destroying structures, on the occasion of subsequent works.
Several methods can be used to carry out the detection of optically invisible networks.
The detection by electromagnetic means is the most commonly used method. This electromagnetic detection can be performed using electromagnetic detectors relying on the active detection of an electromagnetic signal.
A conventional active detection method consists of injecting, using a current generator, an electrical signal into an electrically conductive tracer wire associated with the network to be identified and disposed along the line route of the latter, and this via connection casings installed at regular distances along the network to serve as access points, and of using an electromagnetic detector arranged to detect an electromagnetic field created by an alternating current circulating in the electrically conductive tracer wire.
The document EP 1 305 546 discloses a connection casing including particularly means for introducing and guiding a plug of an electrical signal generator, a first conductive part intended to be connected to the ground, and a second conductive part intended to be electrically connected to an electrically conductive tracer wire associated with the network to be identified, the first and second conductive parts bearing against each other when no action is exerted on the latter, and the introduction and guiding means being shaped such that, when said plug is engaged in the introduction and guiding means, said plug is able, on one hand to bear against the second conductive part connected to the tracer wire in which the electrical signal must be injected, and on the other hand to separate the first and second conductive parts from each other.
When a significant number of distinct optically invisible networks equipped with connection casings as described in the document EP 1 305 546 are located near each other, the detection of a particular optically invisible network proves to be complex.
Indeed, part of the electrical signal injected into the connection casing associated with the optically invisible network to be detected, is likely to propagate, through the ground, in connection casings associated with other optically invisible networks. Such propagation may involve the creation of an electromagnetic field along the tracer wires associated with other optically invisible networks, such electromagnetic field being likely to disturb the detection and tracking of the optically invisible network to be detected.
A solution to overcome this drawback may consist of inserting separation members into the introduction and guiding means belonging to the connection casings associated with the other networks in order to separate the first and second conductive parts of theses connection casings. These dispositions allow to insulate from the ground the tracer wires associated with networks located near the network to be detected, and then to avoid creating an electromagnetic field along these propagation means likely to disturb the detection of the network to be detected.
However, the insertion of separation members within the connection casings proves to be long and tedious, and this, even more when the connection casings are disposed in technical galleries or wall boxes.
Furthermore, such solution requires to dispose and to store a significant number of separation members.
Accordingly, the detection of a network using a connection casing as described in the document EP 1 305 546 proves to be long, difficult and costly.
The present disclosure aims to remedy these drawbacks.
The technical problem underlying the disclosure relates to providing a detection terminal whose structure is simple and economic, and which allows an easy, fast and reliable detection of an optically invisible network, such as a gas, electricity, optic fibers or water (rainwater, wastewater, drinking water) network.